1. Field of the Invention
The present invention relates to a bearing apparatus. In particular, the present invention relates to a bearing apparatus installed in a blower fan.
2. Description of the Related Art
In recent years, electronic devices have been becoming more and more densely packed with components, and electronic components installed in the electronic devices and blower fans arranged to cool the electronic components have accordingly tended to be disposed close to each other. Such a blower fan is arranged to produce air currents through rotation of an impeller, i.e., a rotating body. In addition, the amount of heat generated in the electronic devices has been increasing year after year, and there has been a demand for an increase in rotation speed of the blower fans. However, the increase in the rotation speed of the blower fans leads to an increase in a peak value of vibration in each frequency, and then vibrations may exert harmful effects on the electronic components.
Therefore, in order to reduce vibrations which accompany the rotation of the blower fan, it is necessary to reduce oscillation of an axis of a rotating body of the blower fan. One specific method of achieving this is to adopt a fluid dynamic bearing as a bearing portion to support a circumference of a shaft through a lubricating oil so that vibrations generated in the rotating body can be attenuated. In addition, use of a thrust bearing will contribute to preventing tilting of the shaft. A bearing as described above is disclosed in JP-UM-B 06-31199.